The present invention relates to continuous feed pencil mechanisms, and more particularly to a continuous feed pencil mechanism which is capable of employing leads of more than one diameter size.
Various mechanical lead pencil designs have been marketed in the past which have met with consumer acceptance and a number of feed mechanisms have been proposed for these pencils.
A recent development in the mechanical lead pencil market has been the introduction of a continuous feed pencil which is adapted to take a cartridge containing a plurality of leads, or wherein a number of leads are introduced into the pencil mechanism to be fed singly through the feed mechanism.
The mechanical lead pencils in the marketplace, however, are generally restricted to a single lead diameter due to the construction of the feed mechanism. While there are two common lead diameters, 0.5 millimeters and 0.7 millimeters employed for use in a pencil of this type, the 0.7 millimeter lead generally may not be fed through the front opening in the smaller diameter pencil barrel due to the limited size of the opening to support the 0.5 millimeter lead for which the pencil is constructed. In like manner, the 0.5 millimeter lead, when fed through the front opening in the barrel of a pencil constructed to employ the 0.7 millimeter lead, will break due to the enlarged opening providing inadequate support for the lead protruding from the opening of the pencil.
Quite often, it is necessary that the consumer employ a pencil with 0.5 millimeter lead for use in such activities as engineering or accounting while the consumer may prefer a 0.7 millimeter lead for general writing purposes. It is therefore necessary for a user to have at least two pencils in order to satisfy his needs to obtain adequate and acceptable line quality.
As is evident from the above, it is necessary therefore that the vendor of lead refills for those mechanical pencils on the market today stock various sizes of lead to accommodate the various feed mechanisms found in those pencils which is customary might employ. Additionally, it is often confusing to the owner of a mechanical pencil when buying refill leads to determine which lead size a particular pencil requires and he often finds that in attempting to refill the pencil, he has purchased the wrong size lead.
A need has therefore arisen for a continuous feed lead pencil having a feed mechanism which will accept a plurality of lead diameters.
It is therefore an object of the present invention to provide a mechanical lead pencil of the feed through type wherein the feed mechanism is adaptable to accept a plurality of lead diameters.
A further object of the present invention is to provide a mechanical lead pencil having a feed mechanism accepting a plurality of lead diameters which is manufactured without a radical departure from those continuous feed pencil mechanisms being mass produced.
Yet another object of the invention is to provide a mechanical lead pencil having a continuous feed mechanism which is simple in construction and economical to produce by known production methods.